What is Lemma?

A generally minor, proven proposition which is used as a stepping stone to a larger result.

What is Lemma?

In mathematics, informal logic and argument mapping, a lemma (plural lemmas or lemmata) is a generally minor, proven proposition which is used as a stepping stone to a larger result.

For that reason, it is also known as a "helping theorem" or an "auxiliary theorem".

In many cases, a lemma derives its importance from the theorem it aims to prove, however, a lemma can also turn out to be more important than originally thought. The word "lemma" derives from the Ancient Greek λῆμμα ("anything which is received", such as a gift, profit, or a bribe).